The present invention relates generally to construction using gypsum wallboard, and more particularly, to an apparatus used to apply joint compound to corner paper beads prior to their attachment to joints or corners between adjacent wallboard panels.
Corner beads are elongated, narrow strips of metal or plastic, often having a paper face on one side, and are typically folded or angled along their longitudinal center line to produce a generally v-shaped cross-section. They are made with various angles and corner shapes, including 90-degree angle corners and rounded or so-called “bullnose” corners of various angles. Corner beads are also designed for covering both inside (concave) and outside (convex) corners. For application to an inside corner, joint compound is applied to the outside (convex) faces of an inside corner bead. For application to an outside corner, joint compound is applied to the inside (concave) faces of an outside corner bead. Joint compound is applied to the appropriate faces of the bead, and the bead is then pressed against the corner, with the joint compound forming an adhesive joint between the corner bead and the wallboard corner.
Although wallboard joint compound may be applied to corner beads by hand, this is a time consuming and messy process. Hopper devices have been used to reduce the time needed to apply joint compound to the paper bead and provide for a cleaner process. Such devices typically include a hopper retaining a supply of wallboard joint compound, and a passageway in a bottom of the container where the corner bead is passed through the passageway to receive a coating of joint compound and to provide a guide for locating the corner bead.
Two design criteria of such a device are to increase efficiency and increase cleanliness when applying joint compound to a corner bead. Further, since joint compound generally has a highly viscous property and some compounds set rapidly, it is often difficult to remove unwanted joint compound from the hopper upon completion of a job. Thus, another design criteria of such a device is the ability to readily remove unwanted joint compound.